AD1058

AD1058 is a **preclinical small-molecule ATR inhibitor** being developed for cancer, particularly advanced malignancies with potential utility in **brain metastases** and **leptomeningeal metastases** because of reported **blood-brain barrier penetration**. In a 2024 *Journal of Medicinal Chemistry* publication, AD1058 was described as a **highly potent, selective, and brain-penetrant inhibitor of ataxia telangiectasia and Rad3-related protein**, with good preclinical pharmacokinetics and stronger antiproliferative, cell-cycle-disrupting, and pro-apoptotic activity than ceralasertib in the reported studies. The compound also showed preclinical antitumor activity both as monotherapy and in combination with PARP inhibition, radiotherapy, and chemotherapy, supporting its positioning as a **targeted antineoplastic DNA-damage-response therapy**.